Came across this larvae while out hunting yesterday evening. To give you an idea of the length of the caterpillar, the arrow broadhead next to the caterpiller is right at about 2 inches long. Figure the larvae is about 3 inches. Nearest I can tell, its some sort of silkwork moth. I perused thru your archives and found this exact caterpiller, submitted on 9/9/04. However, the caterpillar could not be identified. Hopefully, this is a little better photo for you to work with. Its got me stumped, as I used to raise Polyphemus and Cecropias, and this don’t look like either! Thanks!
We believe this is a Luna Moth Caterpillar.
Update: January 8, 2017
We just approved a comment that indicates this is a Polyphemus Caterpillar.